Wireless access networks are used to provide terrestrial coverage via placement of base stations throughout the desired coverage area. In order to provide adequate service to the clients, wireless operators constantly evaluate the coverage area of their wireless access networks. Such an evaluation may, for example, be done in the planning phase via coverage calculations based on models for the attenuation of the radio signals, terrain configuration data and the configuration data about the type and placement of the base stations. Such calculations provide, for the area under consideration and for each base station included in the calculations, a reasonably complete indication of the estimated signal strength but only with a limited accuracy, given the necessary simplifications made in the attenuation model and the limited degree of details in the underlying data bases. In their operational processes, wireless operators frequently use drive tests in order to assess the coverage of their wireless access networks. These drive tests consist of measurement routes that are traversed by a measurement terminal often mounted on a vehicle, as illustrated in FIG. 1, where the measurement route is shown with a line 1 and the measurement terminal (vehicle) location is shown as a dot 10. Such measurements provide, for each base station included in the measurement, a reasonably accurate indication of the signal strength but only for the very limited set of locations along the measurement route 1. Besides the drive measurements the operators collect statistical information from the network nodes about events that can be used to roughly indicate coverage problems such as failed connections, inter-radio access technology (inter-RAT) handovers and cell reselections, etc.
The coverage assessment options presented above have a number of drawbacks. One is that the planning process is generally characterised by a certain degree of inaccuracy due to e.g. estimation errors in the radio propagation modelling and/or inaccurate terrain configuration data. Another drawback is that the drive tests provide the coverage assessment only along the measurement route. Moreover, drive tests are too costly for estimation of the overall coverage. Yet another drawback is that the network statistics collection has its basic limitation in that only the signals and events for the terminals that are connected to/camping on the network may be reported (and not the terminals that do not have coverage). Moreover, such statistics can only roughly indicate the locations of coverage gaps.
As the foregoing illustrates, there exists a need in the art for a system and method for generating a coverage assessment in a telecommunications infrastructure in a manner that minimizes or eliminates at least some of the drawbacks of the current approaches described above.